Abstract: Self identity has been a crucial phenomenon in the study field of developmental psychology since Erikson first proposed the concept. Empirical study concerning self identity has been largely based on Marcia’s identity status model. Further researchers like Luyckx try to integrate identity status model with its criticism and modification, thus propose the theory of self identity’s dual-cycle model. According to dual-cycle model, self identity is a construct comprised of five dimensions: exploration in breadth, exploration in depth, ruminative exploration, commitment making and identification with commitment. The dimensions constitute two cycles: "commitment-formation cycle" and "commitment-evaluation cycle", and the dynamic interaction of the two cycles prompts the process of identity formation and development, thus results in six identity statuses: identity achievement, identity foreclosure, ruminative moratorium, carefree diffusion, diffused diffusion and undifferentiated.

Key words: self identity, status model, dual-cycle model, identity dimension